Microfibres of conducting polythiophene and biodegradable poly(ester urea) for scaffolds

Abstract

Hybrid scaffolds constituted by a mixture of conducting and biodegradable polymers have been obtained by the electrospinning technique. Specifically, poly(3-thiophene metyl acetate) (P3TMA) and a copolymer derived from L-leucine which bears ester, urea and amide groups (PEU-co-PEA) have been employed. Both polymers have been selected because of their intrinsic properties and their high solubility in organic solvents. The biodegradable polymer renders continuous and homogeneous microfibers in most of the electrospinning conditions tested, appearing as an ideal carrier for the polythiophene derivative.A spontaneous phase separation has been observed for concentrated solutions of PEU-co-PEA and P3TMA in chloroform:methanol mixtures. The dense phase results enriched on the conducting polymer and can be successfully electrospun giving rise to scaffolds with up to 90 wt-% of P3TMA. Morphologic observations have indicated that continuous and regular microfibers are attained despite the high conducting polymer content. P3TMA presents a high doping level and leads to stable electrospun scaffolds by the simple addition of a low percentage of a high molecular weight carrier. The resulting scaffolds are practically amorphous and thermally stable, presenting also a pronounced electrochemical response and being electrochemically active. Thus, the formation of polarons and bipolarons at specific positions, the ability to exchange charge reversibly and the electrical stability of hybrid PEUco-PEA/P3TMA electrospun scaffolds and P3TMA alone are practically the same.

Semiconducting, biodegradable and bioactive fibers for drug delivery

“…The same approach has also been used to fabricate electroactive biodegradable 3D scaffolds. For example, regular microfibers were recently obtained by electrospinning a mixture of P3TMA and biodegradable poly(ester urea) [25]. Overall the results obtained in this field proved the synergy associated with the combination of biodegradable polymers and CPs, their mixtures showing biodegradability and both electrochemical and electrical activities.…”

“…acetate) P3TMA was synthesized by chemical oxidative coupling polymerization in dry chloroform following the procedure described by Kim et al [34], which was successfully used in previous works [22][23][24][25]. Anhydrous ferric chloride (FeCl 3 ) was used as both oxidant and dopant.…”

Electrospun Scaffolds from Low Molecular Weight Poly(ester amide)s Based on Glycolic Acid, Adipic Acid and Odd or Even Diamines

“…For example, a rapid vaporization of the solvent within the electrospinning jet may lead to the formation of a skin layer which later collapses [23,24]. It has also been postulated that the fiber morphology may depend on the flow rate and specifically flat ribbons seem to be favoured at rates so high that the thin fiber walls become unable to support the increasing fiber diameter and collapse to form the flat ribbons [25].…”

“…The first was derived from the capability to establish strong hydrogen bonding interactions, whereas the second was a consequence of the low/moderate molecular weight of samples. It is well-known that electrospinning requires a minimum molecular weight to form suitable fibers (e.g., poly(ethylene glycol) could not be electrospun when Mn was close to 10,000 g/mol) [21] or alternatively a high molecular weight sample must be added as a supporting polymer [22,23]. Specifically, experiments were performed using 1,1,1,3,3,3-hexafluoroisopropanol as unique solvent while the polymer concentration was varied in the 5%-50% (w/v) range.…”

Electroactive and bioactive films of random copolymers containing terthiophene, carboxyl and Schiff base functionalities in the main chain

“…For example, soluble PTh derivatives have been combined with biodegradable and biocompatible insulating polymers to fabricate 2D [37][38][39][40][41] and 3D [42][43][44] scaffolds; hydrophilic and biocompatible poly(ethylene glycol) (PEG) chains have been grafted to PTh chains to fabricate amphiphilic PTh bottle-brush copolymers; [45][46][47] and biomolecules, such as small peptides 48 or proteins, [49][50][51] have been immobilized into PTh matrices using in situ polymerization approaches. In this work, we combine our interest in Schiff bases with our expertise on bioactive PThs to investigate a new approach oriented towards the development of new platforms for tissue engineering applications.…”